A simple back-projection Compton image reconstruction algorithm was implemented [1]} in order to validate the overall \(\gamma \) -ray imaging performance of i-TED, which relies on accurate energy- and spatial-calibrations. Thus, a point-like \(^{137}\) Cs source with an activity of 325 kBq was attached to one of the capture samples at a distance of 63 mm in front of the S-detector of i-TED (see also Fig. REF ). In a second measurement, the \(^{137}\) Cs-source was lifted 10 cm up in the vertical direction. The resulting Compton images are shown in Fig. REF , thereby illustrating the angular sensitivity of the i-TED imager and the proper implementation of calibrations and spatial reference systems.
